Associations Between Polybrominated Diphenyl Ethers Concentrations in Human Placenta and Small for Gestational Age in Southwest China.

BACKGROUND: Prenatal exposures to polybrominated diphenyl ethers (PBDEs) may affect fetal growth. Small for gestational age (SGA) is a measure based on birth weight and gestational age at birth and represents a good indicator of fetal growth but it has been used only in a small number of studies. The present study aimed to examine the associations between PBDEs exposure and the risk of SGA among participants from a birth cohort in Southwest China. METHODS: The concentrations of eight common PBDE congeners (BDE-28, BDE47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) in 996 human placental samples collected between May to October 2020 were determined. A questionnaire survey was administered regarding maternal characteristics. The outcome data of the newborns were obtained from the medical record. The Mann-Whitney U test and binomial logistic regression analysis were used to assess associations between PBDEs concentrations (as a continuous or categorical variable) and SGA. RESULTS: All PBDE congeners were detected in more than 73% of samples. The median concentrations of ΣPBDEs were 10.08 ng/g lipid weight (lw). BDE-209 was the most abundant PBDE congener, contributed 28% to ΣPBDEs. There were 114 (11.4%) SGA infants. The levels of BDE-99, BDE-100, BDE-209, and the total levels of ΣPBDEs in the SGA group were significantly higher than those in the controls. When classifying the PBDEs concentrations as two categories: low and high, high level of ΣPBDEs was associated with increased risk of SGA [odds ratio (OR): 2.203, 95% confidence interval (CI): 1.453-3.340] after adjusting for potential covariates. The association remained significant when stratifying the data by gender of the newborn (OR: 2.572, 95% CI: 1.337-4.947 for boys; OR: 2.385, 95% CI: 1.315-4.325 for girls). CONCLUSION: The present study adds to the literature by using placenta to measure PBDEs exposure during pregnancy, and provides evidence that prenatal exposure to PBDEs may be associated with the risk of SGA, at least at the levels of exposure in our population.

The associations between exposure to trihalomethanes during pregnancy and adverse birth outcomes: A systematic review and meta-analysis.

The study aimed to examine the associations between the level of trihalomethanes and its metabolites in pregnancy and the risks of adverse birth outcomes. We searched the databases of the China National Knowledge Infrastructure, WanFang, Vip, PubMed, and Elsevier Science Direct from database establishment to July 14, 2021 and performed a systematic review and meta-analysis of observational studies reporting associations between trihalomethanes level and abnormally low birth weight and preterm birth. The pooled odds ratio (OR), pooled risk ratio, and pooled risk difference with their 95% confidence interval (CI) were calculated for risk estimates. A total of 24 studies involving 1,118,037 pregnant women were finally enrolled in the present systematic review and meta-analysis. Our research found that abnormally low birth weight was associated with higher levels of total trihalomethanes (OR = 2.45, 95% CI: 1.28, 4.68; P = 0.007). Unexpectedly, the meta-analysis indicated that higher total trihalomethanes level was associated with lower odds of preterm birth (OR = 0.90, 95% CI: 0.81, 0.99; P = 0.03). Our findings indicate that trihalomethanes exposure might be a risk factor for abnormally low birth weight and that it would be prudent to minimize exposure to trihalomethanes during pregnancy because of the risk of abnormally low birth weight. Given some limitations of the systematic review and meta-analysis, our results should be interpreted with caution.